The present invention relates to a cutting device for a cutting machine and is used more particularly for cutting soft, sticking or dirtying materials, such as a soft metal, sodium, plastics materials, etc.
The cutting machines generally used for cutting soft materials have cutting devices of the type shown in cross-section in FIG. 1. This device comprises a chain 2 having links 4 guided in translation by a chain guide 6, following a cutting plane perpendicular to the plane of the drawing.
Each link 4 has a side plate 8, 10 located on either side of the cutting plane. Two successive links 4 are connected by a connecting link 12 located between side plates 8, 10. A spindle 14 pivotably connects side plates 8, 10 and the corresponding connecting link 12. The latter projects towards the chain guide 6 and is slidingly located in a U-shaped surface formed in said chain guide 6, so that the chain is guided in translation.
Side plates 8, 10 are extended opposite to the chain guide 6, so as to in each case form a cutting tool 16, 18 respectively. Each cutting tool has a curved cutting end, which curves towards the inside of the cutting plane. On cutting a soft, sticking or dirtying material with such a cutting device, cutting waste accumulates in the space 20 formed between the cutting tools 16, 18. Such waste ends up as a mass in front of the cutting end of the cutting tools, so as to greatly reduce the cutting efficiency of the chain and can even lead to the chain jamming in the material to be cut.
One solution would be to provide a scraper, e.g. fixed to the chain guide, able to clean cutting waste from space 20. However, such an arrangement is impossible, because the scraper would be located on the path of the cutting tools and would consequently prevent their movement.
Other cutting arrangements have also been proposed comprising links equipped with cutting tools, whose end projects towards the outside of the cutting plane, the attachment part to the link being located on the latter in the case of a chain whose guidance links are also used for supporting the cutting tools, as in the case of No. CH-A-371 252, or curved in towards the cutting plane when the cutting links are displaced with respect thereto, as in No. FR-A-1 548 796 and U.S. Pat. No. 3,613,749. Thus, the concavity of the section of the cutting tools is oriented towards the outside of the cutting plane, unlike in FIG. 1.
The tools curved in in this way are justified by the wish to obtain a regular, gentle cut, or a smooth-bottomed slot or groove. They are not expressly designed for the materials to which the present invention relates and no special device for cleaning the tools is provided.